From Ref 2 the open-circuit voltage across the terminals of a half-wave dipole aligned
for maximum signal in a field strength of e V/m

e * lambda

V = -------------

pi

where lambda is the wavelength and pi = 3.14159... The terminated voltage at the
receiver is ½ this, as half is lost between the source impedance and the matched
termination.

wavelength is related to frequency where

speed of light (3x108m/s) = frequency * wavelength

Deriving the frequency from the channel number. We know the channels are 8MHz wide, and
channel 21 corresponds to about 470MHz. Channel 44 is therefore (44-21)*8 up on this

f = 8*(channel-21)+470 MHz

= 8*(44-21)+470 = 654MHz

lambda = 3*108/654*106 = 0.46 m

received signal voltage for a dipole

V = 0.5 * 0.095 * 0.46 / 3.14159 = 0.0069 V

Convert this to dBuV

V = 20log10(0.0069/10-6)

V = 77dBuV

This is now increased by the antenna gain. I am using a standard cheap and nasty Maxview
14 element aerial cited by Maplin at 7.3dB gain

so I expect a signal level of 77 + 7.3 = 84dBuV

Final received signal level = 84 dBuV

(the form above also allows for masthead amps and CT100 downlead, not accounted for
here)

I measure 71-74dBuV for BBC2, a difference of 10-13dB. This seems reasonable to me,
given the non-perfect roof mounted antenna

So why doesn't the field strength value agree with Wolfbane then? [I
get 100dBuV/m where Wolfbane
cites 62dBuV/m for this case]

I don't know is the honest answer to that. The calculation up to field strength has
been checked twice and independently calculated to arrive at the same result. CCIR rec
417-3 (now ITU BT417-5 but I'm not going to pay them to look at the update) quotes a
minimum field strength of 65dBuV/m in band IV and 70dBuV/m in band V, in which case the
test receiver would technically be outside the service area of Sudbury if the field
strength were 62dBuV/m. All I can say is that the value I arrive at agrees reasonably with
experiment in the test case.